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<pre>
      SUBROUTINE <a name="CSROT.1"></a><a href="csrot.f.html#CSROT.1">CSROT</a>( N, CX, INCX, CY, INCY, C, S )
<span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">     .. Scalar Arguments ..
</span>      INTEGER           INCX, INCY, N
      REAL              C, S
<span class="comment">*</span><span class="comment">     ..
</span><span class="comment">*</span><span class="comment">     .. Array Arguments ..
</span>      COMPLEX           CX( * ), CY( * )
<span class="comment">*</span><span class="comment">     ..
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">  Purpose
</span><span class="comment">*</span><span class="comment">  =======
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">  Applies a plane rotation, where the cos and sin (c and s) are real
</span><span class="comment">*</span><span class="comment">  and the vectors cx and cy are complex.
</span><span class="comment">*</span><span class="comment">  jack dongarra, linpack, 3/11/78.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">  Arguments
</span><span class="comment">*</span><span class="comment">  ==========
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">  N        (input) INTEGER
</span><span class="comment">*</span><span class="comment">           On entry, N specifies the order of the vectors cx and cy.
</span><span class="comment">*</span><span class="comment">           N must be at least zero.
</span><span class="comment">*</span><span class="comment">           Unchanged on exit.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">  CX       (input) COMPLEX array, dimension at least
</span><span class="comment">*</span><span class="comment">           ( 1 + ( N - 1 )*abs( INCX ) ).
</span><span class="comment">*</span><span class="comment">           Before entry, the incremented array CX must contain the n
</span><span class="comment">*</span><span class="comment">           element vector cx. On exit, CX is overwritten by the updated
</span><span class="comment">*</span><span class="comment">           vector cx.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">  INCX     (input) INTEGER
</span><span class="comment">*</span><span class="comment">           On entry, INCX specifies the increment for the elements of
</span><span class="comment">*</span><span class="comment">           CX. INCX must not be zero.
</span><span class="comment">*</span><span class="comment">           Unchanged on exit.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">  CY       (input) COMPLEX array, dimension at least
</span><span class="comment">*</span><span class="comment">           ( 1 + ( N - 1 )*abs( INCY ) ).
</span><span class="comment">*</span><span class="comment">           Before entry, the incremented array CY must contain the n
</span><span class="comment">*</span><span class="comment">           element vector cy. On exit, CY is overwritten by the updated
</span><span class="comment">*</span><span class="comment">           vector cy.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">  INCY     (input) INTEGER
</span><span class="comment">*</span><span class="comment">           On entry, INCY specifies the increment for the elements of
</span><span class="comment">*</span><span class="comment">           CY. INCY must not be zero.
</span><span class="comment">*</span><span class="comment">           Unchanged on exit.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">  C        (input) REAL
</span><span class="comment">*</span><span class="comment">           On entry, C specifies the cosine, cos.
</span><span class="comment">*</span><span class="comment">           Unchanged on exit.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">  S        (input) REAL
</span><span class="comment">*</span><span class="comment">           On entry, S specifies the sine, sin.
</span><span class="comment">*</span><span class="comment">           Unchanged on exit.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">  =====================================================================
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">     .. Local Scalars ..
</span>      INTEGER           I, IX, IY
      COMPLEX           CTEMP
<span class="comment">*</span><span class="comment">     ..
</span><span class="comment">*</span><span class="comment">     .. Executable Statements ..
</span><span class="comment">*</span><span class="comment">
</span>      IF( N.LE.0 )
     $   RETURN
      IF( INCX.EQ.1 .AND. INCY.EQ.1 )
     $   GO TO 20
<span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">        code for unequal increments or equal increments not equal
</span><span class="comment">*</span><span class="comment">          to 1
</span><span class="comment">*</span><span class="comment">
</span>      IX = 1
      IY = 1
      IF( INCX.LT.0 )
     $   IX = ( -N+1 )*INCX + 1
      IF( INCY.LT.0 )
     $   IY = ( -N+1 )*INCY + 1
      DO 10 I = 1, N
         CTEMP = C*CX( IX ) + S*CY( IY )
         CY( IY ) = C*CY( IY ) - S*CX( IX )
         CX( IX ) = CTEMP
         IX = IX + INCX
         IY = IY + INCY
   10 CONTINUE
      RETURN
<span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">        code for both increments equal to 1
</span><span class="comment">*</span><span class="comment">
</span>   20 DO 30 I = 1, N
         CTEMP = C*CX( I ) + S*CY( I )
         CY( I ) = C*CY( I ) - S*CX( I )
         CX( I ) = CTEMP
   30 CONTINUE
      RETURN
      END

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